The invention is aimed at development of a process for the preparation of antioxidant activity rich extracts of tuberous roots of Decalepis hamiltonii Wight & Arn. Decalepis hamiltonii Wight & Arn., (swallow root) belonging to Asclepidaceae is a monogeneric climbing shrub native of the Deccan peninsula and forest areas of Western Ghats of India. It finds use as a culinary spice due to its high priced aromatic roots. The roots are markedly fleshy, cylindrical (1-6 cm IN diameter) are characterized by a sarasaparilla like taste accompanied by a tingling sensation on the tongue as described in Wealth of India 1952 (Wealth of India 1952, A dictionary of raw materials, CSIR, New Delhi 3: 24). The roots of D. hamiltonii are used as a flavoring principle (Wealth of India, 1990), appetizer (Murthi, P. B. R. and Seshadri, T. R. Proc. Ind. Acad. Sci. 1947; 13A, 221), blood purifier (Jacob, K. C. Madras Agric. Journal. An unrecorded economic product Decalepis hamiltonii W & Arn., Family Asclepidaceae 1937; 25; 176), and preservative (Phadke, N.Y., Gholap A. S., Ramakrishnan K, Subbulakshmi G., J. Food Sci. Technol. 1994; 31, 472). Similarly the roots of this taxon as described by Nayar et al. (1978) (Nayar R C, Shetty J K P, Mary Z and Yoganrasimhan 1978. Pharmacological studies of root of Decalepis hamiltonii W & Arn and comparison with Hemidesmus indicus (L.) R.Br. Proc. Indian Acad. Sciences 87 (B): 37-48) are considered as “Sariva Bheda” in Ayurveda where finds use as an alternative to roots of Hemidesmus indicus in the preparation of several herbal drugs like Amrutamalaka taila, Drakshadi churna, shatavari rasayana and yeshtimadhu taila. The roots contain 92% fleshy matter and 8% woody core. Of late the highly aromatic roots have been subjected to over exploitation by destructive harvesting that has endangered the survival of this plant. In the earlier reports by George et al. (George, J. Perira, J., Divakar, S., Udayasankar, K and Ravishankar, G. A. Current Science, 1999; 77, 501-502) it was observed that the aromatic roots of D. hamiltonii proved to be a potent bioinsecticide on storage pests at lethal and sub-lethal levels (Indian Patent No. 1301/Del/98). The supercritical extracts of these roots proved to be potent antimicrobial agents (George, J., Udayasankar, K., Keshava, N and Ravishankar, G. A. Fitoterapia 1999; 70, 172-174). George, J., Bais, H. P. and Ravishankar, G. A. (Current Science, 2000; 79:894-898) were able to regenerate plantlets of D. hamiltonii W & A from leaf callus. Similarly a method for rooting of Decalepis hamiltonii for field transfer was reported earlier (Bais H P, Sudha G, Suresh B & Ravishankar G. A, Curr. Sci, 2000, 79: 408-410; Obul Reddy, B., Giridhar, P and Ravishankar G. A, Current Science 81(11), 2001, 1479-1482). In Decalepis hamiltonii the tuberous root extracts contains the flavour compound 2-hydroxy-4-methoxy benzaldehyde as a major compound (97%) which is extractable by steam distillation method and followed by using dichloro-methane (Nagaraj an, S., Jaganmohana Rao L., and Gurudutt, K. N., Chemical composition of the volatiles of Decalepis hamiltonii (Wight & Arn.,) Flavour and Fragrance Journal. 16: 27, 2001).
Antioxidants are the compounds that when added to food products, especially to lipids and lipid-containing foods, can increase the shelf life by retarding the process of lipid per oxidation, which is one of the major reasons for deterioration of food products during processing and storage. Synthetic antioxidants, such as butylated hydroxyanisole (BHA) and butylated hydroxytoulene (BHT), have restricted to be use in foods as these synthetic antioxidants are suspected to be carcinogenic (Mahavi D. L., Salunkhe D. K., Toxicological aspects of food antioxidants. In: Food Antioxidants: Madhavi, D L., Deshpande S S, Salunkhe D K, eds.; Dekker: New York, 1995; p 267). In general the oxidation of a metabolic process that leads to energy production necessary for essential cell activities. However, metabolism of oxygen in living cells also leads to the unavoidable production of oxygen-derived free radicals, commonly known as relative oxygen species (ROS) (Mccord J. M., Free radicals and pro-oxidants in health and nutrition. Food Technol. 48: 106-110., 1994; Adegoke G. O, Kumar M. N, Gopalkrishna A G, Vardaraj M. C., Sambaiah K., Lokesh B. R, Antioxidants and lipid oxidation in foods—a critical appraisal. J. Food Sci. Technol. 35: 283-298, 1998), which are involved in the onset of many diseases. These free radicals attack the unsaturated fatty acids of bio-membranes, which result in lipid peroxidation and the destruction of proteins and DNA, which causes a series of deteriorative changes in the biological systems leading to cell inactivation. Thus the identification of antioxidants which can retard the process of lipid peroxidation by blocking the generation of free radical chain reaction, has gained importance in recent years. In living systems, varieties of antioxidant mechanisms play an important role in combating ROS (Aruoma O I, Nutrition and health aspects of free radicals and antioxidants. Food Chem, 32:671-683, 1994). The antioxidants may act by easing the levels of endogenous defenses by up-regulatinig the expression of genes encoding the enzymes such as super oxide dismutase (SOD), catalase or glutathione peroxidase (Halliwell B, Gutteridge J M C. Free Radicals in Biology and Medicine, 2nd Edition, Japan Scientific Societies Press: Tokyo, Japan, 1989).